Power Cable - Raymarine SL72 Owner's Handbook Manual

Chapter 8: Installation 8-11
On a radome scanner, the junction box should provide an 11- or 13-way
terminal strip, depending on the number of power cores in your cable, with a
10 A rating. Also, you should keep the length of the un-screened coaxial cores
to less than 30 mm to maintain EMC conformance.

Power Cable

The SL72 PLUS Pathfinder Radar and SL72RC PLUS Pathfinder Radar/
Chartplotter systems are intended for use on ships' DC power systems
operating in the 10.7 to 32 V DC range (that is, 12 V and 24 V systems, not 32
V systems). A 5 ft (1.5 m) power cable is supplied for connecting the ship's
DC power to the display unit.
If a longer power cable run is required, use the supplied power cable to connect
to the display unit. Then use a suitable connector block to connect the free end
to the extension cable, taking particular care to ensure correct polarity. The
supplied power cable has a cross-section of 2.0 mm .
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Note: For vessels with 24 V power systems, the power cable may be extended
by up to 20 m using a wire gauge of 1.5 mm (AWG 16) or greater, irrespective
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of the inter-unit cable length.
For vessels with 12 V power systems, longer power cable runs may require
larger wire gauges to minimise any voltage drop in the cable. The length and
type of the inter-unit cable also affect the wire gauge required for the extension
power cable. In order to determine the correct supply cable size if the power
cable must be extended, estimate the length of cable between the ship's main
power source and the connector block, and then select the wire size indicated
by the distance and inter-unit cable in Table 8-2 .
For example, you might have a 18" scanner, with 20 m between the scanner
and display unit, that you plan to connect by extending the supplied 15 m
heavy inter-unit cable with a 5 m extension cable. In addition, your 12 V
power supply might be 10 m from the display unit, requiring an extension of
8.5 m. To determine the wire gauge required for the power cable extension,
refer to the table for the 18" scanner, go to the row labelled 15 m Heavy + 5 m
ext, and read across until you come to a maximum cable length greater than
8.5 m. This is the 10 m entry, in the column for 2.5 mm wire gauge.
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